Step down DC-DC converters are well known, and are commonly used in devices as such as computers and smart phone, for example. High-frequency synchronous step down DC-DC converters for battery-powered portable applications provide a dynamic voltage scaling feature, and generate a programmed output voltage transition with a programmed voltage target and a programmed voltage slew rate. These programmable parameters are configured via an interface within the DC-DC converter.
Step down DC-DC converters support low-voltage DSPs (Digital Signal Processor) and processor cores, including submicron processes and their retention modes. These devices also address digital voltage scaling technologies.
Typically, step down DC-DC converters can start a voltage transition in two ways. In one way the microprocessor programs via an interface, for example via I2C, a bit to start the voltage transition. In a second way the microprocessor drives one or more DC-DC converter device external pins to start the voltage transition.
In the second case the voltage transition is started immediately, without the latency introduced in the first case by having to communicate to set the DC-DC device bit which starts the voltage transition. The drawback of the first case is that these small devices need one or more external pins to quickly start the programmed voltage transitions, and one or more voltage target registers are also needed.